THE DELTA BARRAGE AND THE ENGLISH ENGINEERS
At the date of the English occupation the Delta Barrage was generally
thought to be like the whole fabric of Egyptian Government, rotten
to the core. And so indeed it seemed. No one had ever dared to use,
or apparently even to think of using, the Barrage on the Damietta or
right-hand branch at all. The history of the Barrage on the Rosetta
branch was hardly less inglorious. In 1863 its gates were closed
for the first time, but about ten of its arches began to settle, and
ominous cracks showed. Eventually the threatened part was surrounded
by a coffer-dam, and from 1872 to 1883 it managed to hold up about
1 metre. But even that was precarious. Commission after Commission
had condemned the structure; it was felt that at any moment it might
give way, especially if called upon to bear a greater strain, and it
was actually the settled policy of the Government to rely on huge
and costly pumping-stations instead. It was a paltry result after
the expenditure of £4,000,000 and so much labour.
Then, not for the first or last time, the Anglo-Indians came to the
rescue of Africa. Sir Evelyn Baring himself (now Lord Cromer) during
his service as Financial Member of the Council in India, must have
been impressed by the enormous importance of irrigation. It would not
be difficult to find many points of resemblance between his character
and that of one of the greatest, if not the greatest, of the rulers
of India, Lord Lawrence, different as were their spheres of work;
but certainly they were alike in this. As Lord Lawrence supported
Arthur Cotton in his engineering work, so Lord Cromer supported Colin
Scott-Moncrieff and the band of trusty lieutenants—Willcocks,
Garstin, Ross, Brown, Foster, Western, and Reid—who came with
him. Fortunately for Egypt, these men, trained in the best school of
irrigation in the world, possessed not only the highest scientific
skill and knowledge, but were also animated by the best spirit of
the empire-building Englishman. Deep in them lay the earnest wish and
determination, far stronger even than their enthusiasm and love for
their profession, to alleviate the lot of the unhappy peasantry of
Egypt. It was this heartfelt sympathy for the wrongs of the fellaheen,
ground down by the intolerable burden of the corvée, that sustained
them in their ceaseless labours and enabled them to pass successfully
through those dark days, when the air was full of forebodings of
failure and disaster, whose fulfilment would have pleased so many.
The Barrage is situated, as has been said, a little way back from
the point of the Delta. It is really two Barrages, one on the left
or Rosetta branch of the Nile, with sixty-one arches, 465 metres in
length, and the other on the Damietta branch with seventy-one arches,
535 metres in length. Between the two runs a revetment wall across the
intervening tongue of land, 1,000 metres in length. From a distance
it resembles a bridge of rather fanciful design, with the arches set
unusually close together, and, indeed, for a great part of its career
the functions of a bridge were the only ones it performed. The tongue
of land between has been converted into beautiful gardens, planted
with shady trees and many shrubs and flowers, and even a greensward
resembling grass. Altogether, it is one of the most delightful and
beautiful spots in Egypt, besides being one of the most useful. Here
is the starting-point of the great feeder canals which irrigate the
Delta provinces. On the left, facing north, is the Rayah Behera,
which supplies the province of Behera, to the left of the Rosetta
branch. Between the two Barrages is the head of the Rayah Menoufia,
the canal which feeds the two provinces of Menoufia and Gharbia, lying
between the two arms of the river; while on the right is the Rayah
Tewfiki, which, with its supplementary canals, Ismailia, Sharkia,
and Basusia, supplies the three eastern provinces of the Delta,
Kalyubia, Sharkia, and Dakalia. All these canals are navigable,
as well as the branches of the river, and provided with locks for
that purpose. These great waterways are free to all, and few of the
results of British occupation are more appreciated in Egypt. Formerly
all craft upon the Nile had to pay toll on passing under a bridge,
which did nothing but hinder their progress, while those for whose
convenience it was made passed without charge overhead.
A Barrage, as its name implies, is designed to completely bar
the bed of the river, so as to enable it to feed the canals at a
higher level than would otherwise be the case, and also to allow
the flood to pass through it easily. It needs, therefore, a very
solid foundation from bank to bank, on which the arches which hold
the movable sluice-gates can be securely planted. Its construction
is, therefore, a very different and much more difficult matter than
merely throwing a bridge over the stream, even a bridge with several
spans. The difficulty is all the greater when, as here, the bed
of the river offers nothing more substantial than shifting sands
to build upon. It was for this reason that Linant wished to build
the Barrages at leisure in the dry, and then divert the river from
its old channels, and lead it through when they were completed. But
Mougel chose to build his in the existing bed of the river, thereby
increasing the difficulties of actual construction, though from other
points of view there was much to be said for this plan. At the site
of the Rosetta Barrage the bed of the river was not of uniform depth;
he therefore filled up the deepest part of the channel, which lay on
the right, with loose stones, so as to bring it up to the level of
the bottom on the left-hand side. No cement was used in laying down
this barrier, but the Nile mud filled the interstices and made it
water-tight; when finished, this barrier was 60 metres wide and 10
deep at the deepest part. On this and on the natural sand he built
a platform 46 metres in width and 3·5 metres thick, composed of
concrete overlaid with brick and stonework. On the platform he raised
his arches and piers, all built of brick. Each of the openings for
the sluice-gates, sixty-one in number, was 5 metres wide. Like an
iceberg, that part of the Barrage which is visible above water is
much less than the invisible part below. To further strengthen the
structure and keep it in its place, a mass of rubble pitching or
loose stones was thrown into the river on the downstream side. This
talus was 3 to 16 metres in depth, and at one part extended 50 metres
downstream in a kind of tongue, narrowing down to 2 metres. The
Damietta Barrage was built on a similar plan, but its downstream
talus was not so large. Unfortunately, the concrete used for the
platform was inferior, chiefly owing to the fact that Mehemet Ali,
growing impatient at the slow progress of the work, ordered a certain
amount of material to be laid down every day, and laid down it had
to be in defiance of all engineering requirements. The consequence
was that, as soon as the Rosetta Barrage was subjected to strain,
ten of the arches on the left-hand side, where the platform was
laid down on sand only, settled and cracked. It was patched up by
surrounding the injured arches with a coffer-dam; but the Damietta
Barrage never even had its gates put in.
Such was the structure with which the English engineers had to
deal. Even as it stands to-day, it cannot, of course, compare in
magnitude with many works upon the Indian rivers; but as regards
the difficulties to be overcome, it can compare with almost any
in the world. It would have been far easier to rebuild the whole
thing from the beginning, but at the time the necessary funds were
not forthcoming. They had to take the old structure, with all its
imperfections, and screw it up to work as it was. The country could
not afford to cut off the summer water-supply of the Delta while the
repairs were in progress. The cotton-crop had always to be thought
of. And the period of the year during which the summer canals required
to be supplied was the only period during which work could be done,
for once the flood came down all operations were at an end. It is the
glory of the English engineers that, working under these conditions
and with untrained workmen, they succeeded in their task.
The Government was already paying many thousands a year to a company
for pumping water out of the Rosetta branch into the canals during
the summer, and the first thing Sir Colin Scott Moncrieff had to do
on his arrival was to decide upon a scheme which had been prepared
for erecting new pumping-stations at an initial expense of about
three-quarters of a million, and involving an annual expenditure of
at least another quarter of a million. So hopeless were the prospects
of the Barrage assumed to be, that even this expenditure, with a
doubtful result, was thought preferable to repairing it. Sir Colin’s
arrival was only in the nick of time. He determined to see what could
be done with the resources at hand. The new pumping-station scheme
was set aside, and Mr. Willcocks was put in charge of the Barrage.
There was much literature on the subject. During the last sixteen
years nothing had been done, but much had been written, and more
said. Commissions, expert and inexpert, had issued voluminous and
condemnatory reports, and had even prepared expensive schemes of
repair. Mr. Willcocks (now Sir William) is an indefatigable reader,
and could hardly have been encouraged thereby, till an examination
of the structure itself showed that all the later reports had been
drawn up without reference to facts. It had been observed that
whenever the gates were let down there was very severe action of the
water on the downstream side. The authors of the reports concluded
that the foundations were honeycombed. It is characteristic of the
Looking-glass days of Ismail that no one ever thought of trying to
find out by actual observation whether there might not be some other
cause. But Mr. Willcocks, looking for himself, found that this action
of the water was caused, not by honeycombed foundations, but by open
gratings which intervened between the bottom of the sluice-gates
and the platform. They had been put down originally to keep the
silt away from the bottom of the gates. Someone had fixed them so
as to prevent the gates from being lowered to their full extent and
then they had actually been forgotten. Measures were at once taken to
close these gratings, and eventually to remove them altogether. 20,000
cubic metres of rubble pitching were added to the talus. The Damietta
Barrage was likewise strengthened with various ingenious expedients,
improvised to meet the demands of the moment. Sluice-gates were put
in for the first time and gradually closed. Part of it was closed
by a temporary stone dam. Eventually in the summer of 1884 2·2
metres of water were held up on the Rosetta branch, and 1 metre on
the Damietta. Next year the same nursing process was continued. The
coffer-dam round the weak arches was strengthened, the talus of rubble
pitching below each Barrage was completed, and this year 3 metres were
held up on the Rosetta branch and 1·6 on the Damietta. The effect
was extraordinary. The acreage under summer cultivation was doubled,
rising from 600,000 to 1,200,000 acres. Not only was the supply of
water in the Delta canals greatly increased throughout the summer,
but, as it was delivered at a higher level, there was a great saving
of expense in lifting it on to the land. For the first time the
Egyptians thoroughly realized that a new power had come amongst them.
The experiment had been successful, but temporary expedients
could not last for ever. The more water held up, and the greater
the area of the summer cultivation, the more necessary it became
to insure the stability of the structure. A thorough repair would
cost money. Fortunately, this was now forthcoming. Mr. Willcocks’
success had settled the claim of the Barrage to a share in the famous
Irrigation Million borrowed in 1885.
At the end of 1886 the work was begun, under the charge of Colonel
Western and Mr. Reid, sent specially from India for the purpose. The
operations were spread over four years. In the first year the left
half of the Rosetta Barrage was taken in hand and finished before
the flood, next year the right half. In 1889 and 1890 the Damietta
Barrage was similarly taken in hand and finished. Each year the part
to be repaired was enclosed by earthen dams, and the water pumped
out so as to lay the foundations dry. The whole of the existing
floor was raised, both on the upstream and downstream side, and it
was also considerably lengthened. It was, in fact, enclosed in a
new and reliable suit of armour. The dangers and anxieties of the
work were incessant. The protecting dams were always liable to be
breached. Spring after spring burst out through the treacherous bed
of the river, and threatened the destruction of the year’s work;
and again and again each of them was successively stopped by a number
of ingenious devices. There is no enemy so persistent and so insidious
in its attacks as running water. It is always feeling for and finding
out the weak spots. It never sleeps or slackens by day or by night. It
can only be met successfully by a corresponding activity. While work
was possible, it was carried on unceasingly by night as well as by
day. Sometimes as many as 1,600 men worked through the night. The
upper brickwork was generally sound, but new iron sluice-gates moving
in special grooves were fitted throughout. The whole of the repairs
cost £465,000. It was money well laid out. Not only was the safety
of the Barrage assured, but it was found possible to hold up yet
another metre of water. The area of summer crops matured rose once
more from 1,200,000 to 1,520,000.
It might have been thought that the work was now complete. Both in
1891 and 1892 (a year of specially low summer supply) all the water in
the Nile was held up, and diverted into the canals. Not a drop reached
the sea during the summer without having done duty. But the engineers
were now looking forward to a time when the supply would be greatly
increased. The idea of a reservoir had become an affair of practical
politics. It was necessary to make assurance doubly sure. Accordingly,
in 1896 a new experiment was tried—namely, stock-ramming with clay.
Certain arches in the Damietta Barrage were selected, and in them
five-inch holes were bored right down through pier and platform
alike. When the bore-holes were complete, they were lined with iron
tubes. Clay was then forced through the tube by means of an iron
rammer, and as much as could be made to spread out at the bottom
of the hole was put in and rammed. As far as the clay went, the
experiment was not an entire success; but the boring brought to light
a condition of things in the very vitals of the Barrage which demanded
drastic treatment, for the bore-holes proved the existence of large
cavities in the original platform, and in some places there was free
water communication between one bore-hole and another. Some piers in
the Rosetta Barrage were therefore chosen for a similar experiment,
but this time liquid Portland cement was used instead of clay, and
the results were entirely satisfactory. Few discoveries have been of
more signal service than the invention of Portland cement. It is not
too much to say that it has revolutionized hydraulic engineering by
the facilities it affords for constructing solid works in water. Its
strength and resisting power is enormous, but its greatest quality
is that it hardens and solidifies under the action of water, and,
so far as is known, only goes on getting harder and harder with
time. The borings in the Rosetta Barrage having revealed similar
deficiencies to those in the Damietta, it was decided to apply to
both a thorough dose of this invaluable and invigorating medicine.
In 1897 five holes were bored in each pier of the Rosetta Barrage
(their united length amounted to very nearly 6 kilometres), and
into each was poured a quantity of liquid cement. The necessity
for the treatment was proved by the fact that in some cases the
cement travelled right through from the bore-hole in one pier and
rose through the bore-hole in an adjoining pier till it reached
the top. One pier actually swallowed 439 barrels of cement, while
its neighbour took a lesser but still gigantic draught of 327
barrels. There was no doubt that the cement thoroughly explored
and filled all the cavities existing in the foundations under the
bridge. In all, 3,254 barrels were used in the Rosetta Barrage
alone. In 1898 the grouting process, as it is called, was applied
with equal success to the Damietta Barrage.
To use Sir Hanbury Brown’s homely but expressive image, the process
applied to the Barrage was exactly that followed by a cook who wishes
to finish off a cold pie with its proper complement of jelly. The
jelly is introduced into the pie in the form of warm gravy, which
penetrates into and fills every recess of the succulent interior,
and then solidifies as it cools.
And still the engineers were not satisfied. So treacherous is the
river’s bed that no possible safeguards seemed superfluous. It
speaks volumes for the courage and skill of those who in 1885 held
up 3 metres of water with the old unreformed Barrage, that in 1897,
after the successful execution of such great and costly repairs,
it was still thought advisable to undertake completely new works to
assist in the task of holding up 4, or at the most 5, metres.
It is a principle in hydraulics, not easily understood at first
by the layman, that the pressure upon a weir or barrage in a river
depends entirely upon the difference in level between the water on
the upstream and on the downstream side, and not on the mere volume
of water in the river behind it. In December, 1897, the Caisse de
la Dette voted £530,000 for the construction of two subsidiary
downstream weirs, with the object of relieving the pressure on the
Barrage by raising the level of the water on the downstream side, thus
dividing the head of water to be held up into two—in other words,
by making two steps instead of one. Each weir was to consist of a
core of rubble masonry set in cement, sunk well below the bed of the
river, and protected up and down stream by a long slope of rough stone
blocks or pitching. To make the masonry core thoroughly watertight,
a mass of clay puddle was to be put on either side of it. The weirs
were thus to be a solid dam, blocking the course of the stream up to
such a height that the head of water on the Barrage, at that time
amounting to 4 metres, would be reduced to 2·5 metres. The flood
would pass freely over the top of the weirs. At the same time the
sluice-gates of the existing Barrage were to be heightened, so as to
permit the upstream level to be raised 1 metre more in June and July,
so as to take full advantage of the rising flood and facilitate the
early sowing of maize, a great point with the Egyptian cultivator.
By the summer of 1900 this programme had been completed. The building
of the weir on the Rosetta branch was an especially fine performance,
for which great credit was due to Sir Hanbury Brown and Mr. Brooke,
who were in charge of it. Five hundred metres in length, it was begun
at the end of December, 1899, and actually finished before the flood
began to come down in July. The same Portland cement played a great
part in its construction. It may now fairly be said that the Barrage
is complete at last, and fully equal to every strain that it can be
called upon to bear.
The weirs were constructed not a moment too soon. It so happened
that the summer supply of 1900 was lower than in any previous year
of which records have been kept. In 1889 the river sank to a level
of ·60 metre below zero on the Assouan gauge. In 1878 it fell to
·71 metre below zero, and this was the lowest known before the
summer of 1900. But on three days in that year, May 15, 16, and 26,
the river fell to a level of ·91 metre below zero. The position was
aggravated by the extension of summer cultivation. The total extent
of summer crops had risen still further to over 1,700,000 acres.
To save the valuable cotton crop was the earnest preoccupation of the
Irrigation Department. They were able by the most strenuous efforts,
not merely to save the crop, but so to treat it that it gave a yield
which, only a few years before, would have been considered perfectly
impossible even in a good year. But all their efforts would have been
in vain had it not been possible, thanks to the new weirs, to raise
the level of the water upstream of the Barrage to an extent which
would have been exceedingly dangerous without their assistance, and
so to take full advantage of the rising flood. The mere enumeration
of the special measures which were put into force gives a very good
idea of the difficult duties which devolve on those who control the
water in Egypt:
1. Earthen dams were constructed in both branches of the river to
prevent the inrush of salt water from the sea.
2. Special programmes were laid down for ‘rotations’ on the
canals.
The system of rotations, which was introduced from India, is that
the land-owners are only allowed to pump water on to their lands at
certain intervals. There are several advantages in this. The water
is economized, and as it can thereby be kept at a lower level in
the canals, there is less danger of the soil becoming deteriorated
by excessive saturation. The pumps are allowed to work for a certain
period, according to the district, and then an interval is prescribed,
until the expiration of which they are not allowed to work again. In
1900 the pumps were allowed to work for a period of six days at
a time, and at first twelve days was the interval until the next
pumping. But as the summer wore on, and the river continued to fall,
the interval was gradually extended to twenty-two days—a very
severe measure indeed.
3. All land-owners were warned not to sow rice.
4. They were also forbidden to sow maize until a date should be
announced.
5. Special pumping arrangements were made.
6. There was more than usually careful regulation at the heads of
the canals above the Barrage, so as to insure a proper distribution
of the water available to all the provinces.
7. A special staff was appointed to see that all these regulations
were carried out.
Could any government be more paternal than this—it might even be
said, more despotic? But countries which depend on irrigation have a
natural tendency towards despotism. When water is plentiful they may
be as republican and democratic as you please; but when the crisis
of scanty water comes they must have a strong hand over them, just
as the Roman Republic had to have its Dictator in times of national
peril. It speaks well for the good sense of the Egyptians, and it
proves their implicit faith, built up by sixteen years’ experience,
in the English engineers, that even those stringent regulations were
unhesitatingly obeyed, and that breaches of them were so rare as
to be almost non-existent. They had their reward; for while 1878 is
still remembered as a year of black disaster and distress, in 1900
the cotton crop amounted to no less than 5,250,000 kantars,[5] and
the maize crop, in spite of its late sowing, was also very good. Only
the rice, a comparatively insignificant item, was sacrificed to its
more important rivals. Thanks mainly to the good work done by the
completed Barrage, neither the public nor the private finances of
Egypt suffered the least shock from a year of unprecedented scarcity
of water, even when this was coupled with most unseasonable cold
and fogs in September, which considerably diminished the output of
cotton. Lord Cromer had indeed good reason to write in 1901:
‘Had it not been for the labours of the eminent hydraulic engineers,
who for the last seventeen years have placed their services at
the disposal of the Egyptian Government, the most skilful financial
assistance would not have availed both to place the Egyptian Treasury
in a position of assured solvency and to meet in any adequate degree
the constant demands which are the necessary accompaniment of a
policy of reform.’
Such are the outlines of the long history of the Barrage, designed
by Frenchmen and brought to perfection by Englishmen. Both nations
can share in the credit of the work, and it is pleasant to record
once more the generous and graceful act by which the chief of the
English engineers recognised and acknowledged the merits of his
predecessor. Sir Colin Scott Moncrieff discovered Mougel Bey living
in obscurity and oblivion, weighed down by poverty and neglect. It
was owing to his intercession that the poor old man was rescued from
want, and, by means of a pension granted by the Egyptian Government,
enabled to spend his remaining days in comfort and honour. Both
nations are entitled to be proud of this act of poetic justice,
which added a lustre of its own to the glory of the completed Barrage.